KEF LSX Wireless Music System Review

If you’ve seen it, it’s not likely you’ll ever forget it. If you haven’t, please follow this link for what I’m about to reference.

The film follows the hapless protagonist (Chase’s character) Clark Griswold as he inexorably, epically and comically descends into madness while driving his family cross-country on vacation.

There’s several key plot-defining scenes where Griswold sees former supermodel Christie Brinkley’s character throughout the film – usually behind the wheel of a red Ferrari 308 GTS. In one of these scenes Brinkley is cavorting next to the 308 while cranking tunes at a rest stop… Griswold stares at her and unconsciously gets up from the picnic table where he’s having lunch with his family and walks towards her.

He’s completely mesmerized by the sexualized tableaux and starts white-guy dancing with abandon, hardly seeming to notice his antics while locking eyes with her… that was me when I first started listening to the KEF LSX.

I was standing on the other side of the room from where I had installed the diminutive powered speakers, casually setting up my iPad to run the dedicated KEF set-up apps when, after launching Roon, this incredibly wide-open, room-filling sound flooded the space around me. I unknowingly swivelled my head, made eye contact and started moving my hips as I cranked the volume and walked towards the large wall shelves where the LSX were sitting.

I had become Griswold.

As soon as it happened I thought of the scene in Vacation and laughed at myself, but I couldn’t deny the LSX had disarmed me with their sonic authority, much the way the LSX’s big brother – the LS50 Wireless – had the first time I heard them in 2017.

The units can run completely wireless of each other – no tether required – which is amazing for set-up – needing only to be attached via an AC-mains cable (white, supple, two-metres long and provided – one per speaker) and can be configured via the KEF Control app and run via the KEF Stream app. I se up the LSX via the Control app, but then pretty much just used Roon for playback. The system also comes with an ethernet cable (for physically connecting the units for higher-resolution playback ability if you choose) and an elegant, comfortable, easy-to-use remote control.

Digital details

Aesthetically and technically speaking, the two models share a lot of the same DNA – the LSX looks like a miniaturizing ray gun was used on the LS50 – but the LSX benefits from more than a year of further research & development on KEF’s part into proprietary wireless-speaker connectivity, amplification and software/hardware interfacing. It also comes in five colour choices: white, red, green, blue and black (white was my choice, although it lacks the industrial-fabric covering of the other colours). The LSX will support input resolutions up to 24-bit/192kHz. Output is 24-bit/48kHz for wireless playback and 24-bit/96kHz for RJ45 tethered playback. The LSX connect wirelessly via either 2.4GHz/5GHz dual-band wi-fi, Bluetooth 4.2 with the aptX codec (10-metre range, up to eight devices), or hard wired via RJ45 Ethernet. A TOSLINK Optical and a 3.5mm auxiliary input are also included. The LSX also has a 5V2A DC subwoofer output for those who like it to go real low.

Set up

I used a dedicated MacBook Air 11-inch for my Roon Core connected via ethernet to my network and an iPad2 Mini for the Roon Remote. This is my default Roon setup until they send me a
Nucleus to review. I had the speakers firing down the short side of our living/listening room so anyone playing them would be in the sweet spot while stretched out on our sofa with their backs to the sunlit windows (a favourite pastime around here). The LSX has a rated frequency response of 49Hz~47kHz (-6dB), but to be honest, they sounded deeper in-room. A facet I partially attribute to being placed on wall-mounted book shelves with about four inches of space behind them (approximately 56 inches apart, 36 inches high) and having books stacked on the inside edge of each.

There was definitely some boundary-reinforcing going on and while the bass felt large, it never sounded sluggish or boomy. Things had a noticeable improvement thanks to a little help from the KEF Control app which lets you use DSP settings to fine-tune placement parameters. KEF calls this their “Music Integrity Engine.” These parameters include; where the speakers are placed (desk or stands), distance from the front edge of desk, distance to rear wall, room size, room tuning (Dampened, Moderate, Lively), dB-adjustments (-6dB~0dB) for Desk Mode, Wall Mode, Treble Trim, Phase Correction and Bass Extension (Less, Standard, Extra). Dialling-in the DSP helped tighten-up the notes between the lower octaves without it sounding like it had lost any of its punch. Ditto for upper-frequency extension which remained sweet, and airy without sacrificing resolution. Midrange was defined, bouncy, had meat on the bones and instruments like guitars, cellos, stand-up bass, piano and organ carried impact close to commiserate with their size.

For my bedroom, I bought a pair of LSX's and some discounted Boston Acoustics ASX250 subs. I added some KEF 2ft. stands, Mogami cables, Sorbothane hemispheres, 20lbs. of steel shot & another 20 of sand for the stands as well as Auralex Baby GRAMMA platforms and SVS sub feet.

I have a much more expensive system in the basement that's centered around KEF LS50's and Rythmik servo subs, but the set up is very similar as is the way they radiate into the room.

I have 3 take-away's to offer:

• The LSX's are a pretty fantastic product and offer the promise of a great sound system if they would just add a couple bands of parametric EQ into the mix with their setup app so you can take it to the next level and do some real room/playback adjustment. That said, the controls available through the app are very impressive.

• The LSX cabinets are not built to nearly the same level as the LS50's (no surprise given the price point) and they do "sing" (vibrate) a great deal when you turn the volume up even with a 120Hz hi-pass filter working. These are not speakers meant to produce more than 98-100dB even with the hi-pass filter maxed.

• You can never have a truly great sounding system without a great sounding room... already knew that, but, given the commonality of the systems, that has been put into stark relief. My wood floored/drywalled bedroom has nothing, but a bed to absorb sound. The bass is uneven, the mids are a touch overpowering and the stereo image is vague. My main system is in the basement and I'm setting it up as a LEDE room (live end/dead end). It's sounds incredible. I'll forgo the description, but anyone would be and is impressed when they hear it.

One final thought: when you place a tubular speaker stand on top of a sub, even with SVS sub feet, you still need to fill them with steel shot and sand. The difference is not subtle and it's effective & cheap!

I added this into the review, thanks. I used a dedicated MacBook Air 11-inch for my Roon Core connected via ethernet to my network and an iPad2 Mini for the Roon Remote. This is my default Roon setup until they send me a Nucleus to review.

I own my music and store it on a NAS, so I don't have interest in streaming services and am content with JRiver rather than pay for Roon. Will these speakers work as DLNA players under JRiver or other UPnP/DLNA servers? Will its DAC play DSD files as DoP or do they just go silent when fed DSD?